Reports and Studies

Researchers wanted to find out if state medical marijuana laws led to an increase in adolescent marijuana use. They examined past-month marijuana use rates for over 11 million students between the years 1991 and 2011 from states that enacted medical marijuana laws and states in similar regions that had not. Their conclusion was simple; they found no increase in adolescent marijuana use related to the legalization of medical marijuana.

A new report in the International Journal of Drug Policy examined whether more high school seniors would use marijuana if it were legally available. The study analyzed Monitoring the Future data and found that 10.6% of high school seniors who don’t currently use marijuana said they would try it. NOTE: The Monitoring the Future question language did not clarify an age restriction (“If marijuana were made legal to use and legally available, which of the following would you be most likely to do?”), which may either imply or lead survey respondents to believe marijuana would be legal for seniors who are 18 years of age. In already-passed laws in Colorado and Washington, and proposed laws in other states, the minimum legal age for purchase or possession is 21.

Researchers at the Institute for Child Health Policy at the University of Florida College of Medicine examined what effect, if any, medical marijuana laws have on teen use. U.S. anti-drug officials like the drug czar have said such laws decrease the perception of risk and therefore lead to an increase in teen use. Looking at data from 2003-2011 from Montana, Rhode Island, Michigan, and Delaware, these researchers found "no discernible pattern suggesting an effect on either self-reported prevalence or frequency of marijuana use." They conclude that passage of medical marijuana laws does not measurably affect adolescent marijuana use.

Replicating a prior study, but controlling for state characteristics and measurement error, researchers found that medical marijuana laws have little discernible impact on teen marijuana use or perceptions of the risk of marijuana use in those states. In fact, their research showed that passage of medical marijuana laws actually resulted in a slight decrease in teen marijuana use.

Using data from the national and state Youth Risk Behavior Surveys and other government sponsored data collections, researchers from the Universities of Washington, Oregon, and Colorado at Denver found no association between medical marijuana laws and increased teen marijuana use. They concluded, "[o]ur results are not consistent with the hypothesis that legalization leads to increased use of marijuana by teenagers."